Top 20 Hardest Secret Bosses in Video Games

“Splatoon 2” (2017)

For the most part, you’ll have a much easier time dealing with the single player mode of “Splatoon 2” than attempting its breakneck-speed multiplayer. That is, until you reach the end of its DLC, the Octo Expansion. To even reach this hidden boss, you have to collect all eighty mem cakes, which obviously takes quite a bit of time. Inner Agent 3 is a nightmare, utilizing ridiculously high accuracy with a variety of weapons across five phases. They also have high maneuverability, meaning it’s a lot easier for them to dodge your attacks than the other way around. Needless to say, you’ll go ‘splat’ at least a few times.

“Cave Story” (2004)

True to the Metroidvania genre, “Cave Story” gets pretty tough. This is especially the case in its hidden final level, the appropriately named Blood Stained Sanctuary. You’ll need a few secret items to get inside, and at the end of a brutal gauntlet, you’re met by Ballos. He brings the pain across four phases; his first uses deadly lightning attacks and dashes around with alarming speed, his second requires hitting him in the eyes as he bounces around to squash you, and the third comes in two parts, sending out multiple flying eyeballs to annihilate poor Quote. If you want the game’s best ending, you better be prepared to fight for it.

“Yakuza 0” (2017)

The dual protagonists of “Yakuza 0” each have a secret boss that becomes unlocked once you’ve completed all of their side quests. Both of them have a multitude of health bars and can be pretty annoying. Goro faces off against Jo, who can put harmful items in your empty inventory slots that, frustratingly, look like helpful ones. All of his combos are deadly, but he pulls out a dagger at half health and gains access to one that can destroy your entire health bar. Kazuma faces off against So, who uses guns, including a laser that’ll put you down in a couple of shots. His second phase features a helicopter that drops furniture, which stuns you, and medicine that can make either of you briefly invincible.

“South Park: The Fractured but Whole” (2017)

In “The Fractured but Whole,” Morgan Freeman puts up a surprisingly tough fight. To access the fight, all you have to do is visit his taco shop, go behind the counter, and punch him three times. But you should only do so if you’re high level and have a ton of resources, because you’re going to need them. He has the highest health of any boss in the game, at 9,999, and has big AOE attacks that can hit multiple party members. One of his attacks is a devastating fart that can even knock out a party member instantly. Oh, and his second phase gives him twice the amount of moves, while the third phase sees him Charm your party members.

“Sekiro: Shadows Die Twice” (2019)

FromSoftware’s main bosses are known for their brutality, so you can imagine how infuriating the studio’s secret ones can be. After defeating the Divine Dragon in “Sekiro,” players can face off against the Demon of Hatred back in the Ashina Outskirts. Its Posture bar is basically as long as its health bar, meaning you can’t rely on the game’s signature Posture Break mechanic to save you. Across three phases, the Demon will utilize a plethora of fire-based attacks, both ranged and melee. And some of his others are even unblockable. With this much damage to go around, Demon of Hatred is an accurate name.

“Octopath Traveler II” (2023)

He may have been the standard final boss in the first game. But Galdera’s secret battle in “Octopath Traveler II” shows he was holding back. Players can face him after completing a couple of lengthy side quests, and no matter what, he’ll make you feel underleveled and unprepared. You have to use all eight party members, splitting them across two phases; meaning, you can’t just pick and choose your favorites, leveling them up and giving them the best gear. During Phase One, he uses three Souls that act as guards and can deal deadly counter attacks if hit by damage they aren’t vulnerable to. Phase Two is the true test, as each section of its body has its own health bar and overpowered attacks to contend with.

“Hollow Knight” (2017)

The Radiance already offered a sizable challenge as the final boss of “Hollow Knight.” But Absolute Radiance, at the end of the “Godmaster” DLC? That thing is on a whole other level. Reaching it is already a pain since it sits at the end of a long boss rush you’ll have to make it through without dying. Most of the attacks can also be found in the original fight. It’s just that they’re faster, stronger, and, in the case of ranged moves, feature a larger number of projectiles. Across six phases, Absolute Radiance will do its best to squash our little hero like the bug he is. And reaching the end is a Herculean task.

“Final Fantasy VII” (1997)

While some would claim Ruby Weapon is the tougher of the two hidden superbosses in this RPG classic, we believe the Emerald Weapon beats it just by a hair. You’ll find it at the Bottom of the Sea via submarine, though it’s not something we personally like to seek out. Much of the stress of the fight comes from the twenty minute time limit. But even without it, the boss has some dangerous attacks. Each of them deals several thousand points worth of damage, some even hitting the entire party at once. That means you’ll have to spend a lot of time healing with either items or spells. That’s not even taking its own defense and health into account, which is understandably hefty.

“NieR: Automata” (2017)

You wouldn’t expect a little robot merchant to have much fight in him, but Emil packs a lot of power. In order to face him, you must have completed the lengthy side quest, ‘Emil’s Memories.’ On a second playthrough, you’ll then be able to find his home where a level 99 boss fight awaits you. It doesn’t help that the room is pitch black, but Emil would still be a force to be reckoned with in the light. As one of the highest level bosses in the game, every attack is deadly, especially his spinning lasers and exploding copies of his own head. He also offers a second fight later, which is just as big of a pain as this one is.

“Undertale” (2015)

To unlock the hardest fight in “Undertale,” and one of the hardest in any indie game, you have to follow the Genocide Route. That means killing every monster in every single area, to the point where they stop spawning. Sans will make you pay for your bloodlust. His attacks come quicker than most players’ reaction time will be able to handle. The little heart that represents you is sure to get obliterated as his attacks come at lightning speed. Truly, there’s no way to make it through without a lot of trial and error, and it can be utterly maddening. Who’d have thought this goofy skeleton could throw down so hard?

“God of War Ragnarök” (2022)

Step aside, Sigrun; the real Valkyrie Queen is here. After putting an end to the vile Odin in “God of War Ragnarok,” you can take on the optional task of cleaning up his remaining supporters. This includes Gna, leader of the All-Father’s most capable warriors. As we’d come to learn, Gna puts even Thor to shame in her lust for blood as evidenced by a tough-as-nails brawl. Similar to the 2018 game’s secret fight, you’ll be met with unbelievable strength and speed befitting the highest of enemy levels. Her elemental attacks deal a lot of damage, she’s hard to predict, and her unblockable grabs are infuriating. She’s a fitting final obstacle for the God of War.

“Bayonetta” Series (2009-23)

The Umbran witch has had to face a lot of challenging foes over the years, but most can’t hold a candle to Rodin. Thankfully, the weapon smith is usually an ally to Bayonetta. But he’s there for for players who want the game’s ultimate challenge. His fight in the original game is unlocked after collecting 10,000,000 Halos. He moves with incredible grace and speed as he easily pummels you into submission. He’s impossible to stun and his dangerous combos can knock off gigantic chunks of health at a time; meanwhile, he has multiple health bars to work through. He’s kept up this legacy by appearing as a secret boss in the sequels.

“Persona 5 Royal” (2020)

The optional fight against Justine & Caroline in “Persona 5” is certainly worth mentioning. But in the updated version, “Royal,” the two reform as Lavenza. And she is far worse. She can only be fought on a New Game Plus towards the end of the story. She can remove your party’s buffs and her debuffs and features four phases, the first three of which require you to deal 5,000 damage within 9 turns. Each phase also has a specific gimmick, forcing you to adapt with different Personas. You’ll have to deal Technical damage during the second, and land a Critical Hit at least once per turn during the third. If you fail to adhere to these rules, she can end the fight immediately.

“Super Mario RPG: Legend of the Seven Stars” (1996)

It may be a Mario game, but it’s also from the studio behind “Final Fantasy.” “Super Mario RPG” is a beloved blend of Nintendo’s mascot and Square’s mechanics and design. Part of that design is including an absurdly hard secret boss that’ll make you question how good you are at the game. Culex comes from an alternate dimension in search of strong fighters. In the battle, you’ll also have to contend with four crystals, all of which use different elemental attacks. They collectively have over 12,000 HP. And while you can just go for Culex, the impressive amount of damage that comes from all five combatants makes that a poor choice.

“Kingdom Hearts II Final Mix” (2007)

Found only in the “Final Mix” version of the game, Lingering Will is one of the toughest boss fights “Kingdom Hearts” has to offer. You can face this optional baddie after beating the game and completing all worlds, which opens a portal in Disney Castle. The boss wastes no time mounting an offensive of intimidating attacks with ferocious speed. The possessed armor can also change its Keyblade’s shape for different types of attacks. As if he isn’t bad enough to deal with, there are his support drones that chase you around, firing lasers. This fight requires you to perfect the timing of your most powerful attacks, which must be done in small windows when the Lingering Will isn’t hurling damage your way.

“Dark Souls III” (2016)

Of the many spirit-crushing fights players can find in the “Dark Souls” series, the Nameless King is one of the greatest sources of rage. After ringing the bell of the Great Belfry, you can square off against him at the Archdragon Peak. He’ll choose not to fight fair during his first phase, riding his pet Wyvern around. Naturally, the beast has some heavy attacks to watch out for, but the rider is who you should really fear. He’s much faster and stronger than the average boss from the series, and his lightning attacks can be a particular pain. Both the pet and the master also like to attack from above, so it’s a fight that constantly has you on your toes.

“Final Fantasy IX” (2000)

The “Final Fantasy” series has clearly known its fair share of well-hidden and ridiculously powerful optional foes, fittingly dubbed superbosses. Which of these fights is the hardest varies from player to player. But Ozma is certainly a piece of work. Players face it in Chocobo’s Air Garden after the longest side quest in the game and should expect a high level of frustration. It knows Curse, which can inflict multiple status effects at once to all party members, and Meteor, which does a random amount of damage up to 9,999. It can also absorb your party’s MP and heal as a counterattack, which it will probably do when it’s close to death.

“Kingdom Hearts III” (2019)

To reach this secret boss in the “Kingdom Hearts III: Re Mind” DLC, you first need to deal with a boss rush featuring thirteen different fights. And Yozora is certainly a discouraging prize for your efforts. He’s incredibly fast normally, but can also teleport for good measure, making the fight hard to get a grip on. His attacks also come in a variety of ranges and combos, most of which can deal heavy damage. And his own durability makes dealing damage a tedious process. As if that wasn’t bad enough, he can also possibly steal your health and items. The only way to claim victory is patience and the acceptance of many, many deaths.

“Elden Ring” (2022)

FromSoftware has crafted a reputation for delivering the most challenging bosses in gaming. So, when “Elden Ring” released in 2022, fans everywhere made it their mission to track down the most demanding enemy within. Who they found, and were likely promptly destroyed by, was Malenia, Blade of Miquella. Fought at the end of an optional dungeon, the Demi-God can easily close the distance between you and unleash a flurry attack that will quickly and drastically drop your HP. During her second phase, her attacks gain the Scarlet Rot status effect, which deals damage over time. That’s not to mention the fact that every hit she lands heals her, which only adds to the stress.

“Megami Tensei” Series (1987-)

After playing the role of protagonist in “Shin Megami Tensei III: Nocturne,” the Demi-Fiend went on to become the hardest optional boss in the series, and all of gaming. He has appeared in several entries and will prove an insurmountable challenge to most players. For starters, any party members with moves that counter his abilities will be insta-killed at the start of the fight. He has no weaknesses himself, he’ll constantly cycle through minions to keep fighting you, and he’ll fully heal himself once he reaches half of his 60,000 HP. That’s not even going into his attacks, all of which deal major damage and one of which has a chance to insta-kill and targets the whole party.

What’s a secret boss you got stuck on for hours? Share your painful memories in the comments, and be sure to subscribe for more great videos every day!